A victim's sandal is pictured near the Shiite Baqir-ul Ulom mosque after a suicide attack, in Kabul, Afghanistan, Monday, Nov. 21, 2016. An Afghan official says that dozens of civilians have been killed after a suicide bomber attacked a Shiite mosque in the capital. (AP Photos/Massoud Hossaini)

Ismail Kawasi, spokesman for the Public Health Ministry, said Monday that at least 45 others were wounded in the attack. Kawasi added that at least one small child is among the dead.

Faredoon Obiadi, head of the criminal investigation department for the Kabul police, said the attacker detonated his suicide vest among the crowds inside the Baqir-ul Ulom mosque in western Kabul.

The attack took place on the first floor of the two-story building where Shiite worshippers had gathered to commemorate the death of Imam Hussein, the Prophet Muhammad’s grandson and an iconic Shiite martyr, in Karbala, Iraq in 680 A.D.

“I was inside the mosque and the Mullah was reading the prayer, suddenly a huge explosion happened then everywhere was dark,” said Ewaz Ali, 50 who suffered minor injuries.

No group has yet claimed responsibility but militant Sunni fundamentalists like the Taliban and the Islamic State group view Shiites as apostates and frequently attack Shiite mosques and public gatherings. Monday’s bombing struck a ceremony commemorating 40 days since the anniversary of Hussein’s death. In early October, at a gathering commemorating the actual death anniversary, militants attacked another Shiite shrine in Kabul, killing 14.

Amnesty International’s South Asia Director Champa Patel said, “The attack on a Shia mosque in Kabul is a horrific and deliberate attack on civilians. The Afghan authorities must investigate this crime immediately and bring the perpetrators to justice. They have a duty to take effective measures to protect Shia Muslims from attacks and end impunity for previous abuses against the Shia community.”

Shiites in Afghanistan make up an estimated 15 percent of the population of around 30 million. Their public celebrations and commemorations were largely banned during the five years when the Taliban controlled the country. But Afghanistan’s Shiites have become more public since the extremists were overthrown in the U.S. invasion of 2001.

In July this year, a suicide bomber targeted ethic Hazaras, who are mostly Shiite, as they marched through central Kabul to protest discrimination. At least 80 people were killed and more than 200 wounded in the blast that was claimed by the Islamic State group.

In 2011, at least 54 people were killed when a suicide bomber detonated his device at a Kabul shrine where hundreds of people had gathered.